﻿// ----------------------------------------------------------------------------------
// <copyright file="ModularKeyInfoFactory" company="NMemory Team">
//     Copyright (C) 2012-2014 NMemory Team
//
//     Permission is hereby granted, free of charge, to any person obtaining a copy
//     of this software and associated documentation files (the "Software"), to deal
//     in the Software without restriction, including without limitation the rights
//     to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//     copies of the Software, and to permit persons to whom the Software is
//     furnished to do so, subject to the following conditions:
//
//     The above copyright notice and this permission notice shall be included in
//     all copies or substantial portions of the Software.
//
//     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//     AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//     LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//     THE SOFTWARE.
// </copyright>
// ----------------------------------------------------------------------------------

namespace NMemory.Indexes
{
    using System;
    using System.Linq.Expressions;
    using NMemory.Exceptions;
    using NMemory.Modularity;
    using NMemory.Services;
    using NMemory.Services.Contracts;

    public class ModularKeyInfoFactory : IKeyInfoFactory
    {
        private readonly IKeyInfoService service;

        protected ModularKeyInfoFactory(IKeyInfoService service)
        {
            this.service = service;
        }

        public ModularKeyInfoFactory(IDatabase database) 
        {
            this.service = database
                .DatabaseEngine
                .ServiceProvider
                .GetService<IKeyInfoService>();

            if (this.service == null)
            {
                // Fallback
                this.service = DefaultServiceConfigurations.CreateDefaultKeyInfoService();
            }
        }

        public IKeyInfo<TEntity, TKey> Create<TEntity, TKey>(
            Expression<Func<TEntity, TKey>> keySelector) where TEntity : class
        {
            IKeyInfo<TEntity, TKey> result;

            if (!this.service.TryCreateKeyInfo<TEntity, TKey>(keySelector, out result))
            {
                throw new NMemoryException(
                    ErrorCode.GenericError, 
                    ExceptionMessages.CannotCreateKeyInfo);
            }

            return result;
        }
    }
}
